Outline

Objective

The purpose of this prospective study was to evaluate the cumulative incidence, duration and time course of cerebral vasospasm after traumatic brain injury (TBI) in a cohort of 299 patients.

Methods

Transcranial Doppler (TCD) studies of blood flow velocity in the middle cerebral (VMCA) and basilar arteries (VBA) were performed at regular intervals during the first 2 weeks post-trauma in association with 133Xe cerebral blood flow (CBF) measurements. According to the current definitions of vasospasm 5 different criteria were used to classify the patients: Criterion A (VMCA>120 cm/s), B (VMCA>120 cm/s and Lindegaard Ratio (LR)>3), C (anterior Spasm Index (SI) >3.4), D (VBA>90 cm/s) and E (posterior SI>2.5). Criteria C and E were considered hemodynamically significant vasospasm (HSV). Mixed effects spline models were used to analyse the data of multiple measurements with inconsistent sampling rate.

Results

Overall 45.2% of patients fulfilled at least one criterion for vasospasm. Patients who developed vasospasm were significantly older and had lower Glasgow Coma Scores (GCS) on admission. The normalised cumulative incidence was 36 and 37% for Criteria A and B, respectively. Anterior HSV (Criterion C) was found in 44.6%. However, basilar vasospasm (Criteria D and E) was found in only 19% and 22.5%, respectively. The most common day of onset for Criteria A-B and D-E was post-injury day (PID) 2. The highest risk of developing anterior HSV was found on PID 3. The daily prevalence of vasospasm on the intensive care unit was 30% from PID 2-13. Vasospasm resolved in 50% of patients after a duration of 5 days for Criteria A-B and after 3.5 days for Criteria D-E. Anterior HSV resolved after 2.5 days in 50% of patients. The time course of HSV was primarily determined by a decrease in CBF.

Conclusions

The incidence of vasospasm after TBI is similar to that following aneurysmal subarachnoid hemorrhage. Because vasospasm is a significant event in a high proportion of patients after severe head injury, close TCD and CBF monitoring is recommended for the management of such patients.